How to install programs on my mac without needing the pword?

I have a mac osx provided by my school and I would like to install many programs on this mac but every time I choose the location for the program to install I use the hard drive for the location and then thats when it prompts me for the pword! They already blocked disk image mounter and I just use the disk utility to open dmg files. Is there a way to get around this? AND PLEASE NO BULL CRAP FROM PEOPLE WHO SAY THAT I SHOULDN'T ATTEMPT THIS!!!!!!